<template>
  <div class="spec-preview">
    <img :src="imgObj.imgUrl" />
    <div class="event" @mousemove="boxMove($event)"></div>
    <div class="big">
      <img :src="imgObj.imgUrl"  ref="bigImg"/>
    </div>
     <!-- 遮罩图 -->
    <div class="mask" ref="moveMin"></div>
  </div>
</template>

<script>
  export default {
    name: "Zoom",
    props:["PassImage"],
    data(){
       return {
         index:0
       }
    },
    methods:{
    boxMove(e){
     let mask=this.$refs.moveMin
    
     let left=e.offsetX-mask.offsetWidth/2
     let top=e.offsetY-mask.offsetHeight/2
     let bigImg=this.$refs.bigImg
    if(left<=0)left=0
     if(left>mask.offsetWidth)left=mask.offsetHeight
     if(top<0)top=0
     if(top>=mask.offsetHeight)top=mask.offsetHeight
     mask.style.left=left+"px"
     mask.style.top=top+"px"
     bigImg.style.left=-2*left+"px"
     bigImg.style.top=-2*top+"px"

     }
    },
   computed:{
     imgObj(){
      return this.PassImage[this.index]||{}
     }
   },
   mounted(){
      this.$bus.$on("passIndex",(val)=>{
         this.index=val
      })
   },
  }
</script>

<style lang="less">
  .spec-preview {
    position: relative;
    width: 400px;
    height: 400px;
    border: 1px solid #ccc;

    img {
      width: 100%;
      height: 100%;
    }

    .event {
      width: 100%;
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      z-index: 998;
    }

    .mask {
      width: 50%;
      height: 50%;
      background-color: rgba(0, 255, 0, 0.3);
      position: absolute;
      left: 0;
      top: 0;
      display: none;
    }

    .big {
      width: 100%;
      height: 100%;
      position: absolute;
      top: -1px;
      left: 100%;
      border: 1px solid #aaa;
      overflow: hidden;
      z-index: 998;
      display: none;
      background: white;

      img {
        width: 200%;
        max-width: 200%;
        height: 200%;
        position: absolute;
        left: 0;
        top: 0;
      }
    }

    .event:hover~.mask,
    .event:hover~.big {
      display: block;
    }
  }
</style>